The present invention concerns a catalyst for producing hydrogen gas from carbon monoxide and water. The invention also concerns a procedure for producing hydrogen gas from carbon monoxide and water in the presence of a catalyst. The transfer reaction of water gas CO+H.sub.2 O.rarw..fwdarw.CO.sub.2 +H.sub.2 is used for producing hydrogen and for increasing the hydrogen content of synthesis gas. The most important areas of industrial application are hydrogen production, Fischer-Tropsch synthesis and ammonia synthesis. The reaction is exothermic, and therefore highest conversion in equilibrium is achieved at low temperature. The pressure has no effect on the equilibrium.
Metal oxide mixtures have been used as heterogeneous catalysts for the reaction (Satterfield: Heterogeneous Catalysis in Practice, McGraw Hill 1980). In a process operating at high temperatures of 325.degree. to 550.degree. C., a mixture of iron oxide Fe.sub.3 O.sub.4 and chromium oxide Cr.sub.2 O.sub.3 has been used. High temperatures are indispensable for achieving sufficient reaction speed. The pressure in the process is about 3 MPa. The high operating temperature of the catalyst is a disadvantage, because there is carbon monoxide in the reaction equilibrium, which has to be removed in ammonia synthesis, for example.
For the transfer reaction of water gas, heterogeneous cataysts operating at lower temperatures have also been developed, which are used in association with high temperature catalysis. These catalysts contain copper oxide CuO, zinc oxide ZnO and aluminium oxide Al.sub.2 O.sub.3. The operating temperature is about 200.degree. C. and pressure is about 1.3 MPa.
Both catalyst types are pyrophoric and must therefore be handled under oxygen-free conditions.
Catalysis of the transfer reaction of water gas may also be achieved with homogeneous catalysts in a solution at low pressure and temperature. Rhodium and iridium carbonyl iodides (U.S. Pat. Nos. 4,151,107 and 4,107,076) along with other group VIII metal compounds (U.S. Pat. Nos. 3,490,872 and 3,539,298) for example, may serve as catalysts.
However, the industrial application of homogeneous catalysts of the prior art has been prevented by the low activity thereof.